Natural killer (NK)-cell lymphoma is a type of non-Hodgkin lymphoma (NHL). Most NHLs (90%) are of B-cell origin. NK-cell lymphomas do not arise from B-cells. However, controversy still exists over the normal cell from which NK-cell lymphomas arise. In particular, whether NK-cell lymphoma represents the presence of a true NK cell or merely the presence of a T cell with abnormal cell markers is under debate. In the absence of unequivocal proof of the exact lineage of NK-cell lymphoma, many investigators prefer to use the term NK/T-cell lymphoma (NKTCL) when classifying this condition.
Natural-killer T-cell lymphoma (NKTCL) is particularly prevalent in Asian countries and some parts of Latin America. It accounts for up to half of all mature T cell lymphoma cases in Asia (1). However, compared to the more common B cell lymphomas, very little is known about its molecular characteristics and pathogenesis. There has been little progress in basic science and clinical research in this subtype of lymphoma, which continues to constitute a major challenge in managing these patients as there is currently no accepted standard first-line treatment for NKTCL. Despite multi-agent chemotherapy and involved-field radiotherapy, the 5-year overall survival is approximately 9% for non-nasal NKTCL and 42% for nasal NKTCL (2, 3).
Compared to B cell lymphomas which are relatively more common, very little is known about the molecular characteristics and pathogenesis of NKTCLs. This may be in part due to relative rarity in the West and difficulty in obtaining adequate biopsy. Treatment of NKTCLs with conventional chemotherapy has thus far yielded poor results and the outcome is almost always fatal for patients with stage III or IV disease.
It is desirable to identify novel genetic aberrations and potential treatment targets in NKTCL, as well as potential therapeutic agents for NKTCL.